2.8.4. DPPH radical scavenging assay
DPPH assay was carried out as described by Oyaizu (1986)and Bae and Suh (2007). A standard curve of ascorbic acid (y = 10.145x, r2= 0.9907) was prepared and results were reported as micrograms of ascorbic acid equivalent (AAE) per ml juice extract. The radical scavenging activity was calculated accordingly:
where Acontrol is absorbance reading of control and Asample is absorbance reading of the sample.